[Bully69]

Just by way of comment I am very impressed with your level of problem solving here. I watch with interest as I have followed many of your changes with mine having the same kind of behavior…o2 sensors are next for me…

 

[4xchamp]

STOP!
Don't you guys have anyone that can access live data and freeze frame data on a scan tool?
Don't burn resources.

 

[Kory Nunn]

STOP!
Don't you guys have anyone that can access live data and freeze frame data on a scan tool?
Don't burn resources.

Labour is substantially more expensive than parts, and everything I've replaced is something that could do with being replaced after nearly 20 years.

I've done some logging via OBD2 and it also suggests an 02 sensor issue.

As you can see, one sensor is moving rapidly as it should, and the other is very lazy.

 

[Kory Nunn]

Update:

New cats are here:

So far I've removed the right hand side cat, and the upstream doughnut just fell apart:

This absolutely cannot be good for O2 sensor readings, as this would have been letting oxygen in post-combustion. Also, shaking the old cat, I can hear the core moving around, so probably a good thing I've decided to do this before anything catastrophic happened.

Good news is the new cats seem to fit nicely. They are maybe 5mm longer than the OEM's but that's not too much.

I need to source new doughnuts from somewhere, OEM one's aren't offensively expensive, but they require international postage, and I'm pretty impatient.

 

[LpZero]

You can remove the driver side out the top if you remove the cross bar bolts and head shielding on the dry oil sump. Your passenger side gap doesn't look that great. I've found some manufacturers could be using early Gallardo geometry. Hope you have some muffler movement not shown but I had to have my cats corrected.

 

[Kory Nunn]

You can remove the driver side out the top if you remove the cross bar bolts and head shielding on the dry oil sump. Your passenger side gap doesn't look that great. I've found some manufacturers could be using early Gallardo geometry. Hope you have some muffler movement not shown but I had to have my cats corrected.

You mean passenger side

Yep I got it out by loosening the cross member and unbolting the back box. I'm guessing it was a lot easier that stock because I've got the tubi exhaust, which came out easily without removing the back bumper.

All that's left now is to put it all back together

 

[4xchamp]

Labour is substantially more expensive than parts, and everything I've replaced is something that could do with being replaced after nearly 20 years.

I've done some logging via OBD2 and it also suggests an 02 sensor issue.

View attachment 356651

As you can see, one sensor is moving rapidly as it should, and the other is very lazy.

I get it. Looks like you're making progress. For sure the exhaust leak would skew O2 sensor function.
Awesome and good luck!

 

[Kory Nunn]

Quick update: I've designed my own gaskets and they are being manufactured currently for much much less than OEM cost.

For the time being I've wrapped the joint with titanium header wrap, which has let me do some short testing drives. The wrap does leak, but very little.

So far:

• Idle improved, though not perfect.
• Temperatures drastically reduced. After most drives with the OEM cats, the backfire tube and thermocouple connectors would be glowing a dull red. With the new cat's there is absolutely no hint of glow, which would suggest they are running 100deg C or more cooler.
• Cleaner and louder sound <- The best bit

I did get a P0346 (To be 100% honest I think this was the code, I forgot to screenshot) which is 'INTAKE CAMSHAFT POSITION SENSOR Repetition of the same sector of the cam signal after one revolution of the crankshaft. 20 times' after a full throttle 1st -> 2nd shift. The car immediately shut down bank 1.

I had just removed the bank 1 intake VVT solenoid and cleaned it with carby cleaner, maybe relevant? I have 2 new solenoids arriving Monday so I can quicky rule this out. I reset codes and restarted, killed, restarted the car, and it drove fine. I've since driven the car a short while since and it had no issues.

TL;DR: Cats improved idle, improved EGTs, improved sound, but not 100% solved hunting idle.

 

[Bully69]

Did you install new O2 sensors?

 

[Kory Nunn]

Did you install new O2 sensors?

I'd already replaced the right sensor, and when I did the cats I also did the left sensor, and they now read pretty much in line with each other, which makes me think the sensors were fine but the dead gaskets letting air in pre-cat was contributing to issues.

 

[Kory Nunn]

Ok a few more short drives, a bit more idling, and honestly the car is behaving much better.

Idle is now relatively stable, oscillating maybe 100-300rpm, no deep surging, no backfiring noises.
Temperatures are notably cooler, after 15mins at idle, I can put my hand within a few mm of the cats and the radiant heat is just warm.

O2 sensor voltages are cycling more frequently Trims are more reasonable, reading lean or rich in the range of 3-10s before switching. This seems slow to me, but then, this is an old system, and the OBDII codes for "Locked lean" and "Locked rich" are 30s and 60s respectively, so I'm guessing it's just a slow loop.

Vid of engine bay at idle:

Vid of dash at idle:

So far very happy with the cats, with a brandname like Millionare Racing I was a bit dubious but they seem great.

Access is now VASTLY improved, and the locations of O2 sensors/other bits are better than OEM.

Ignore the dodgy header wrap at the back, my custom gaskets are nearly done..

 

[Kory Nunn]

Great news! I've had new gaskets manufactured.

Apparently they are also the same part for Murcielagos and both Pre and LP Gallardos

Best price I could find were $200USD for 2, I was able to get these for substantially less.

Will install this weekend and report back.

 

[Kory Nunn]

Installed. I got impatient. The idle seems fixed.

They fit perfectly, I'm really happy how they turned out. Huge success!

 

[B-Dub]

Hmm, wonder if I have a similar issue, as mine will hunt, especially in warmer weather and running the A/C.

 

[Kory Nunn]

FYI I'm now selling the gaskets cheaper than any other I could find online

 

[Chrishiznit]

So the fix was those gaskets ? Or a combo of everything mentioned above ?

 

[Kory Nunn]

So the fix was those gaskets ? Or a combo of everything mentioned above ?

The issue seemed to have been caused by 2 things that combined to make it really bad:

Primary: The gaskets had failed, which let air in before the O2 sensor, tricked the car into running rich, which caused the cats to get crazy hot (>600deg C) causing the gaskets to fail more, cat overheat codes etc.

If you get:
P1401, P1402, P1405, P1406, I'd suggest looking at your header -> cat gaskets.

If you replace your gaskets it's probably worth replacing your O2 sensors at the same time, especially if you've had elevated temps for a long time. I've seen my O2 sensors glow red, which cannot be healthy.

Secondary: The intake and exhaust VVT solenoids were seized, which affected vacuum, and in turn fuel trims due to having a vacuum-affected fuel pressure regulator. I feel like this may have contributed to gasket degradation by throwing trims out, which causes elevated exhaust temps, which kills the gaskets faster.

If you feel torque decrease as you increase throttle at low RPM, ~2500, there's a good change you need to replace your VVT solenoids. They are so cheap and easy to change that if you haven't changed them, you may as well do it anyway, the part number is 06E109257J, you need 4, and they are like $20 -30 each.

 

[Narudock]

Lose the booster, it will eff up everything. You're playing with fire and assuming significant exposure.
Updated version!? Lol

Hey, I’m curious what type of issues you’ve had with booster in the past? I have the sprint booster on my 2006 Gallardo and haven’t had any issues but am considering turning it off if it is in the best interest of the Gallardo.

 

[4xchamp]

Hey, I’m curious what type of issues you’ve had with booster in the past? I have the sprint booster on my 2006 Gallardo and haven’t had any issues but am considering turning it off if it is in the best interest of the Gallardo.

Use your ankle, save your car. May not harm old cars but newer cars are too sophisticated and rely on accurate throttle data input for systems to function. It put two of my cars in limp mode and caused another to become inoperable until I removed it and cleared faults. His "Tech people" LOL never helped, never offered refund, and said I was the first to experience issues. Read my thread. Charlatan

 

[Kory Nunn]

There has been a development!

I've been looking into the FPR being the issue for a while, as they can leak fuel past their diaphragm directly into the intake plenum, causing weird fuel trims. I've already checked Bank 1 regulator which was fine, replaced it with a new one, and swapped it back, with no change. I kept coming back to the reg though because my symptoms were so aligned with it having issues. But I've replaced it and no change, so not the reg, but also it looks exactly like the reg is leaking fuel into the intake plenum, but I checked it with a clear tube:

And there's no fuel, so it's definitely not the regulator.

And then last night, just as I was trying to get to sleep I remembered something.

The Gallardo has variable intake geometry, and at idle, Bank 1 draws intake from Bank 2's plenum.

Bank 2's fuel pressure regulator is hooked up to Bank 2's intake plenum, which feeds Bank 1 at idle.

Bank 2 fuel pressure regulator can mess up Bank 1 trims at idle!

So I threw the clear tube on Bank 2 FPR and:

Bank 2 FPR has a slow fuel leak through the membrane, which is letting unmetered fuel into Bank 2 plenum during high vacuum. This could be what's causing rich lambda spikes in Bank 1 when coming back to idle, causing the trims to overcorrect lean, causing rough idle.

I've thrown a very cheap reg on for now, and it seems to be driving and idling a little better, and I have 2 new Bosch units in the post.

Lesson learned: Don't isolate banks when hunting for problems!